Gonial Angle.

What the gonial angle is

Stand in front of a mirror and trace your finger along the bottom edge of your jaw, from chin to ear. Just before you reach the ear, the jaw bends sharply upward — that bend is the gonial angle (also called the mandibular angle). Anatomically it’s where the horizontal body of the mandible meets the vertical ramus that runs up to the temporomandibular joint.

The angle is measured on the inside of that corner:

• ~110–120° — sharp, near-90° corner. Reads as masculine, dominant, “model jaw.” Common in classically attractive male faces.
• ~120–125° — neutral / mixed. Works on both sexes depending on the rest of the face.
• ~125–135° — softer, more obtuse corner. Reads as feminine and youthful. Within range for female attractiveness; pulls down a male jawline score.
• >135° — weak jaw. Reads as recessed regardless of sex.

The gonial angle does not move much in adults — it’s set by puberty and by chewing-load during growth. But how it reads on camera depends heavily on body fat, head posture, and lighting.

Why it dominates jawline scoring

A “good jawline” is mostly four things: the gonial angle, the distance from chin to gonial point (mandibular length), the projection of the chin, and the lack of submental fat. Of those four, the gonial angle has the highest visual weight because it’s what makes the side-profile silhouette look sharp or round.

Three reasons it’s so heavily rewarded in male faces:

1. Sexual dimorphism — sharper gonial angles are testosterone-driven. They’re a clean signal of male hormonal development through puberty (see sexual dimorphism).
2. Silhouette clarity — a sharp corner casts a clean shadow and produces a defined edge in photos.
3. Pairs with the masseter — a well-developed masseter muscle sits right on the gonial corner. A sharp angle plus a flared masseter is the “model jaw” look.

How it’s measured

Clinically, the gonial angle is measured from a lateral cephalogram — a side-view X-ray. From outside, you approximate it:

• Side-profile photo, head level (Frankfurt horizontal plane)
• Draw a line along the lower edge of the mandible
• Draw a line up the back edge of the ramus
• The angle between them is your gonial angle

Fazly’s scan estimates this from a single front-and-side photo set using the soft-tissue silhouette, then corrects for body-fat and posture effects to give you a “structural” estimate that’s closer to the underlying bone reality.

Can you change your gonial angle?

The bone angle itself? Not without surgery. After about age 21 the mandible is fully ossified. What you can change is how the angle reads from outside:

• Lose body fat — submental and jowl fat round off the gonial corner visually. Going from 18% to 12% body fat can swing apparent jawline score by 10–15 points.
• Build the masseter — chewing hard gum (mastic) or doing controlled jaw resistance work hypertrophies the masseter, which makes the gonial corner look sharper.
• Mewing — long-term tongue posture is claimed to influence mandibular development. Effects on adults are debated; effects on the apparent silhouette via better head posture are real and immediate.
• Head posture — chin tucked back, head down rounds the gonial angle visually. Head up, chin slightly forward sharpens it.

Surgical options exist (gonial angle reduction for those who want a softer jaw, sagittal split osteotomy for those who want more chin projection) but they’re significant procedures.

What Fazly does

Your scan returns a numeric gonial angle estimate plus a “structural vs. soft tissue” breakdown — i.e. how much of your jaw score is bone (fixed) vs. fat/muscle (changeable). This is the single most useful number in the entire scan for users trying to decide between gym + diet and the surgery route.

Track it every 4–8 weeks. Most natty improvements are masseter growth and fat loss, which together move the apparent gonial angle by 3–5° over a few months.